U.S. patent application number 17/291741 was filed with the patent office on 2022-01-13 for vehicle headlight having a light source.
The applicant listed for this patent is DAIMLER AG. Invention is credited to Alexander GROGER, Bernd SCHNEIDER.
Application Number | 20220010940 17/291741 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-13 |
United States Patent
Application |
20220010940 |
Kind Code |
A1 |
SCHNEIDER; Bernd ; et
al. |
January 13, 2022 |
VEHICLE HEADLIGHT HAVING A LIGHT SOURCE
Abstract
A vehicle headlight includes a light source and an adjustable
objective. The light source is designed as a field having a
plurality of microlight sources. The adjustable objective includes
at least three lens groups, at least two of which are designed to
be displaceable along the optical axis in order to adjust the focal
length and the focal plane.
Inventors: |
SCHNEIDER; Bernd;
(Gartringen, DE) ; GROGER; Alexander; (Stuttgart,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIMLER AG |
Stuttgart |
|
DE |
|
|
Appl. No.: |
17/291741 |
Filed: |
October 21, 2019 |
PCT Filed: |
October 21, 2019 |
PCT NO: |
PCT/EP2019/078546 |
371 Date: |
May 6, 2021 |
International
Class: |
F21S 41/63 20060101
F21S041/63; B60Q 1/00 20060101 B60Q001/00; B60Q 1/08 20060101
B60Q001/08; F21S 41/20 20060101 F21S041/20; F21S 41/153 20060101
F21S041/153 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2018 |
DE |
10 2018 008 760.4 |
Claims
1-9. (canceled)
10. A vehicle headlight, comprising: a light source having a field
comprising a plurality of microlight sources; and an adjustable
objective comprising at least three lens groups, wherein at least
two lens groups of the at least three lens groups which are
displaceable along an optical axis of the vehicle headlight to
adjust a focal length and a focal plane.
11. The vehicle headlight of claim 10, wherein the microlight
sources have microLEDs or micromirror devices.
12. The vehicle headlight of claim 10, wherein the field 30,000 to
1.5 million microlight sources.
13. The vehicle headlight of claim 10, wherein each of the at least
three lens groups has at least one optical lens.
14. The vehicle headlight of claim 10, wherein the adjustable
objective has at least one aperture diaphragm.
15. The vehicle headlight of claim 10, wherein the adjustable
objective additionally contains an iris diaphragm.
16. The vehicle headlight of claim 10, wherein one or more surfaces
of one or more optical elements of the adjustable objective are
aspherical, and have diffractive structures or an anti-reflection
coating.
17. The vehicle headlight of claim 10, wherein materials of
individual optical elements of the adjustable objective have
different refractive indices.
18. The vehicle headlight of claim 10, further comprising: DC
motors, stepper motors, or piezo actuators arranged to displace the
at least two lens groups.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] Exemplary embodiments of the invention relate to a vehicle
headlight having a light source and having an adjustable
objective.
[0002] Vehicle headlights having a light source and an adjustable
objective are known in principle from the prior art. In this
regard, for example, reference can be made to DE 10 2006 053 019
A1. Here, the adjustable objective comprises at least one movable
lens which cooperates with a reflector and a gas-discharge lamp as
light source. This affords the possibility of correspondingly
expanding the beam of light, i.e., ultimately varying the
magnification of the projection in the plane of illumination by
adjusting the focal length. In practice, this is associated with
the disadvantage of blurring, since a sharp image is only possible
in a plane of illumination, predefined by construction, at the
corresponding focal length. Such blurring is a serious
disadvantage, particularly if parts of a full beam cone are to be
hidden by means of appropriate measures, for example to reduce the
glare for oncoming traffic.
[0003] However, trends in technology are increasingly moving in
precisely this direction. Thus, for example, the surroundings of
the motor vehicle are to be detected by environment sensors. The
objects detected are then classified and, if required, illuminated
by a corresponding actuation of the light source of the headlight
or even excluded from illumination, for example oncoming vehicles,
so as not to dazzle them. In this regard, DE 10 2015 013 271 A1
describes a structure with an LED pixel light source which can
achieve this. Then, DE 10 2015 013 271 A1 describes, inter alia,
that sharply focusing optics would be desirable in order now to
place this desired light image of the light source into the plane
of illumination and thus "onto the road" as it is actually
intended. However, the disadvantage is that corresponding optics
only enable an actual sharp image at precisely one distance.
However, depending on the traffic situation, there may be different
distances of the plane of illumination, which can lead to problems.
For this reason, the document proposes a movement between the
optics and the field of the pixel light sources, which is effected
by tilting the field of the pixel light sources.
[0004] In practice, this is relatively complex and relatively
limited in terms of focusing at different distances. Moreover, it
is not possible to achieve independent adaptation of the size of
the image in the plane of illumination, since the beam of the light
source cannot be expanded, since the focal length remains
substantially the same.
[0005] Headlights or spotlights with variable objectives are
likewise known from the further prior art, and in particular here
from the field of stage illumination technology, for example from
WO 2011/020920 A1 or from DE 20 2011 000 481 U1.
[0006] Exemplary embodiments of the present invention are directed
to further improving, in terms of its intended purpose, a vehicle
headlight, in particular a front headlight for a vehicle, having a
light source and an adjustable objective.
[0007] The vehicle headlight according to the invention first of
all uses a field having a plurality of microlight sources as light
source, contrary to the previous headlights known from the prior
art. Such a field having a plurality of microlight sources, for
example microLEDs or micromirrors, which transmit the light in a
targeted manner in the desired direction, or else deflect it
therefrom, allow for very sharp resolution of the resulting light
image. The definition of a plurality of microlight sources
according to the present description covers a structure which has a
number of more than 10,000, in particular between 30,000 and 1.5
million, microlight sources.
[0008] This structure of a vehicle headlight having a field having
a plurality of such microlight sources is now additionally provided
with an adjustable objective. Contrary to the objectives known from
the prior art, this objective has the particularity of comprising
at least three lens assemblies, at least two of which are designed
to be displaceable along the optical axis in order to adjust the
focal length and the focal plane. The objective of the vehicle
headlight having the plurality of microlight sources is therefore
designed such that it can adjust the focal length, and therefore
the magnification, on the one hand, and on the other hand can adapt
the focal plane. Such an objective was hitherto not used in this
way in vehicle headlights, in particular in vehicle headlights
having a plurality of microlight sources. Its operating principle
substantially corresponds to that of a zoom lens, as known from
photography. The inventor has discovered that using this the other
way around in the vehicle headlight now makes it possible on the
one hand to accordingly adapt the size of the image in the desired
plane of illumination and at the same time to focus the image in
the desired plane of illumination. Thus, all of the disadvantages
of the prior art described at the outset are prevented in the
vehicle headlight according to the invention.
[0009] A very high resolution image due to the plurality of
microlight sources can therefore now be displayed at the desired
size and with a high degree of sharpness in the desired plane of
illumination, when viewed at any desired distance from the vehicle.
The image of the specified light-dark distribution, which results
from the calculations of an intelligent light control system in a
manner known per se, in particular via the data from environment
sensors in the vehicle, can therefore be placed "onto the road"
very precisely and exactly in the respective desired plane of
illumination.
[0010] According to an advantageous development of the concept,
each of the lens assemblies has at least one optical lens, and
therefore the size and sharpness of the image of the light-dark
distribution on the road can be influenced over a correspondingly
large magnification range. Here, furthermore, an aperture diaphragm
may be provided, and/or one or more of the surfaces of one or more
elements of the objective can be aspherical. Here, the materials of
the individual elements of the objective can have different
refractive indices, such that different materials or materials with
different densities can be used, in particular in order to achieve
a simple and compact structure. Of course, optical optimizations
such as diffractive structures on the surfaces, anti-reflection
coatings or variable liquid lenses or the like can be used
additionally.
[0011] A further highly advantageous configuration of the headlight
according to the invention additionally or alternatively provides
for the positioning of individual or several elements of the
optical system relative to one another and/or the positioning of
the whole optical system relative to the light source to be
effected by DC motors, stepper motors and/or piezo actuators.
[0012] Further advantageous configurations of the concept also
emerge from the exemplary embodiment which is described in more
detail below with reference to the figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0013] The figures show:
[0014] FIG. 1 a schematic diagram of a vehicle in a view from above
with a projection of a light-dark distribution in various sizes
produced by the front headlight of the vehicle in a plane of
illumination;
[0015] FIG. 2 an exemplary adjustable objective for use in the
headlight according to the invention in a first extreme
position;
[0016] FIG. 3 an exemplary adjustable objective for use in the
headlight according to the invention in a second extreme
position;
[0017] FIG. 4 a schematic depiction of the light cone of the front
headlight of a vehicle in the extreme position shown in FIG. 2;
[0018] FIG. 5 a schematic depiction of the light cone of the front
headlight of a vehicle in the extreme position shown in FIG. 3;
[0019] FIG. 6 an exemplary depiction of a simulated full beam
distribution in the extreme position depicted in FIG. 2; and
[0020] FIG. 7 an exemplary depiction of a simulated full beam
distribution in the extreme position depicted in FIG. 3.
DETAILED DESCRIPTION
[0021] The depiction of FIG. 1 shows a birds-eye view of a vehicle
1. The possibility of emitting light with different focal lengths
and thus with a different beam expansion from the front headlights
4 of the vehicle, which are not visible here, is shown in front of
the vehicle 1 as a light image 2 in a plane of illumination
designated 3. Here, the solid line three-dimensionally depicts a
small magnification 2a, the dashed line a correspondingly larger
magnification 2b, of the light image 2 in the plane of illumination
3.
[0022] In order now to achieve both the desired size 2a, 2b of the
light image 2, and also a high degree of sharpness of the light
image in the plane of illumination 3, the vehicle headlight 4 can
be constructed in the manner depicted schematically in FIG. 2. The
vehicle headlight 4 has, as light source, a field 5 of microlight
sources, which are controlled by an intelligent light control
system, not shown here, such that they give out a light-dark
distribution as light image 2 for projection onto the road and in
the plane of illumination 3. As can be seen in the schematic
depiction from FIG. 2, this light image 2 is now emitted along an
optical axis 6 into the environment. In the process, it passes
through three lens assemblies K 1, K 2 and K 3. The lens assembly K
1, which here has for example two lenses 7, 8 and an aperture
diaphragm 9, is not displaceable along the optical axis 6 in the
exemplary embodiment shown here, and is accordingly fixed. Thus,
there is a defined distance to the field 5 of the microlight
sources. The lens assembly K 2 likewise consists of two lenses 10,
11 and, as accordingly indicated by the arrow designated 12, is
displaceable along the optical axis 6. In the exemplary embodiment
of FIG. 2 shown here, it is depicted directly adjacent to the lens
group K 3 with a lens 13 and thus in one of its extreme positions,
namely the "minimum focal length" extreme position. The emerging
light cone designated 14 is correspondingly wide. The lens group K
3 is also displaceable, as indicated by the arrow 15.
[0023] The aperture diaphragm can also optionally be designed to be
displaceable. An additional iris diaphragm may also likewise be
present in the headlight.
[0024] In the depiction of FIG. 4, a plan view of the vehicle 1
shows, in this "minimum focal length" position of the lens groups K
1, K 2, K 3 of the front headlight 4, roughly what the
schematically depicted light cones 14 look like. They become
correspondingly wide very quickly, and are particularly suited to
large-area illumination of a plane of illumination 3, not shown in
more detail here. The possibility of displacing in particular the
lens groups K 2 and K 3 relative to the lens group K 1 and relative
to one another makes it possible to precisely adjust, in addition
to the desired width of the emerging light cone 14, the sharpness
in the plane of illumination 3, such that, in the desired plane of
illumination 3, an image of the field 5 of the microlight sources
is given both in a variable size and with a desired degree of
sharpness, typically the maximum possible.
[0025] FIG. 6 shows, in this situation of the "minimum focal
length" position, the light distribution using a corresponding
simulation, with the light distribution being accordingly brightest
in the center and the values decreasing towards the edge, as can be
seen from the various scales of grey in the depiction in FIG.
6.
[0026] The depiction in FIG. 3 now in turn picks up the same
depiction as in FIG. 2. The lens assembly K 2, with its two lenses
10, 11, is now in its other extreme position, namely in the
"maximum focal length" position. The emerging light cone 14 is
therefore correspondingly narrower and extends to a greater
distance, in order to be able to illuminate objects at this greater
distance in a targeted manner and to be able to recognize them.
FIG. 5 in turn shows, analogously to FIG. 4, the corresponding view
of the vehicle 1 with the emerging light cones 14 from above.
Particularly by directly comparing the figures, it can be very
clearly seen that the schematically depicted emerging light cones
14 are correspondingly narrower here and therefore also provide a
higher light intensity even at a greater distance. This can also be
seen from the depiction in FIG. 7. Analogously to the depiction in
FIG. 6, here again the simulation of the light distribution is
depicted. Overall, the illuminated area in the plane of
illumination 3 selected by way of example is correspondingly
smaller; hence, the light intensity in the center is considerably
higher.
[0027] Between these two described extreme positions of the maximum
focal length in FIGS. 3, 5 and 7, and also the minimum focal length
in FIGS. 2, 4 and 6, any desired intermediate values can also be
set. This allows the image of the field 5 of the microlight sources
in the desired plane of illumination 3 to be displayed at the
required size and with the required degree of sharpness, such that
a plurality of different illumination subjects can be observed with
the vehicle headlight 4 according to the invention, in particular
also adaptive illumination in the sense described at the outset, in
which objects detected using environment sensors can be illuminated
in a targeted manner or even not illuminated, for example in order
to prevent dazzling oncoming traffic or dazzling oneself by the
very bright illumination of a traffic sign or the like.
Furthermore, objects in the environment can be illuminated in a
targeted manner, in order to be able to better identify and
classify these using environment sensors, for example cameras or
the like.
[0028] Although the invention has been illustrated and described in
detail by way of preferred embodiments, the invention is not
limited by the examples disclosed, and other variations can be
derived from these by the person skilled in the art without leaving
the scope of the invention. It is therefore clear that there is a
plurality of possible variations. It is also clear that embodiments
stated by way of example are only really examples that are not to
be seen as limiting the scope, application possibilities or
configuration of the invention in any way. In fact, the preceding
description and the description of the figures enable the person
skilled in the art to implement the exemplary embodiments in
concrete manner, wherein, with the knowledge of the disclosed
inventive concept, the person skilled in the art is able to
undertake various changes, for example, with regard to the
functioning or arrangement of individual elements stated in an
exemplary embodiment without leaving the scope of the invention,
which is defined by the claims and their legal equivalents, such as
further explanations in the description.
* * * * *